SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dad261c3286e658c85b00b682a7eccb04ab66c7f4ef98e50d7be10750c479e8d' 
  AND token = '+UhwJJyQw3YnwTXQrzyx4znVL5PdhG4Hc4wQ10Svv0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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