SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98edfe49fc0b34e7543d236e9e94c11b1a51af8074b3549d31bdf7565bf538cf' 
  AND token = 'CXhfSKusM/hUw6xiB+myj/c/J7glNZA5XBt72xNq9Xk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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