SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57d49867c3c74899468d69b0387575ba0fddcacd4520ffd54f6ce853107fb3da' 
  AND token = 'TE3sLQWhnoINJGwbdOa7z0xkzcja1pEiV60ogQN0gM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}