SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42e62c5fe970b17f0c9aa00562301cef2afd93891fcc9958c10183c6f59c9ef6' 
  AND token = 'VSxPiyVkASTJWsXwgHuHingxq7ZCrBUTFcNDskEmFuQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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