SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1753b49eb64ba6a30483f31a5051912c7932ccd4ce8b64e9688379017b28318e' 
  AND token = 'fT9ayDRcuxHimxOVt8fOVyhCHrrQcBsSka4fl8yUtCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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