SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83636afd223c2442311126af051baf0b1bc9bb9f4ae8bf3795ebbcdb7ad2475f' 
  AND token = 'BqmpzBs6hqHR74WAfvmw9LmyZ5PijrAIXWZwZZGns3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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