SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d4ee3191255364720eb6bdaf880bcb54786f1906b511947357119c83935e9db' 
  AND token = 'fK/1V0KUSHCcvvmVjPLVp3yOQYuEmSGk/+ySOK9C2JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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