SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92d4f0937f76faa0ed81c859e2717b48579096a39bdc9ce899383f48a2f0213c' 
  AND token = 'yUYPhG7fFGiSORjwkJzz6EuOjvTWOi+39lyo0lYJB0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}