SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cc53b2c0aa31563ea3f96bf248edac8d2c88567c6fb7cfc4381ad316dd5cba1a' 
  AND token = 'RK/PkqdxkY1WhFhxXPXJIhhvgNULINx+QGuTuAIKoEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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