SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd83904302b43dee13ef062f4aebf5d57bdb0b040aa45f567bc4368f59887cc78' 
  AND token = 'MXqEXbyk0cF57G0TlSrBMbzUEbCBUmRGEjtEa8pySkU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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