SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a1885bc747d750ccf2a38d34c6a9b21ad80395b63002a11fd47b705775ea2437' 
  AND token = 'PnALIAV8Xnowr7Drex4S8TjTI6Zh5wTqGT+9OFNxCGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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