SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c162c3bc542e12662b143709d90e86a9af03116f220032fec7d46856dacef2bd' 
  AND token = 'n2jh2D1bT4Kog1ZKVGFXHtmXdYIsu6Y1lmkI06df8S4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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