SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df9d52b349a923da6d0533686ff0c8054ae42e31f57fb202e7b2df3cb4ae2a6c' 
  AND token = 'kTURipEKPMJYlpq6L9QzbkuBoYB/VX9tGF7ClHmNiAY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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