SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '112ca4f227446ce37ba644d5543472718bcf459f78703ccd5758087f46e698a3' 
  AND token = 'ZJ9vFIcOsVVB3K1kGIo1yHejEn0SnpCawFR9WyhNJKE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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