SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d39d192daf56daa384bc1f8764ef340f1cf8493c9dacd7404abc7cfa90616e4' 
  AND token = 'm/v+z1ZVgJZwXxI3Gu3yb1v1YdNCESlgQaNPTLh+yw8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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