SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '90f00bdb0dd360e2c6b510902b5d38569ac285cac5b44d772ebef6ea9aa67820' 
  AND token = 'Y2buWT08lbS1d2F1z5VRjQ59GNSCloCrcoS3+iEgEIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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