SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de1872d1396f774f67aa07591b93180092b15955a03c8cfc3269e8e69c64f489' 
  AND token = 'uBcZ6Vbkp2rMBWS5nHEMC5uKg9PLuQivHZGkh3+/03E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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