SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a73c43f67f0c83f4cdb53b55b8fe93bab6711a9b543ebd2a2e5e6744f39782d' 
  AND token = 'l8p9uY7fXErWuzGTjZg1YdEt5vzBvaMwsgQhpgzPKo8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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