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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d1e3ebf50ad4955b8312c8ae489176f9b7a4ed9cc0fd14ae1cbd2dc9304537a' 
  AND token = 'xcQaTEAcIdwJvTAlUzetIDJnxhISOx932D+p5oPCtDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}