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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3e188d607ca3b451c0748ce2c978e064368feaabfdb3f9ecdf784ab52fd266c' 
  AND token = '6g+Mzy9RuWAeH36/eDyuWqeN9jnbg1CE+Yh3bLI/MMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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