SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ad9839fdd3fdbeb61b0951689b8ce7da0a7f81134070f5ab1d9d6a14595a375' 
  AND token = 'XiXmwmIKdwjBLlvbKfBZOmJHKqvO028ME4UvC2mdG5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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