SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91cb42ad504bdc15230c367cb6ca947b43b8b56f406b579e36c5bbcfbff1416e' 
  AND token = 'WvMtv1atrBzH6ZtTBxxjHAQFHDK8Q1keEEpCIXDh0N4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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