SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f8e7321fd537b94c31ca5f2ffeba2b71b7ed59e3cd9f66aac61395d097e50f8' 
  AND token = 'Ek6UAxYLIid+Ok8r8gU6Oqmtto2PGLn5FXDhi7X1rmI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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