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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd42f5be337265083964ab990d0ea2dadea11e55837b4403e4b6b3383c378ea5a' 
  AND token = 'Wdn4/fywBSnuv0HE6pgRlNfxwpeZcziwT+Uc0b+LDoQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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