SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdb239cc357c804b6fd7a696f22b34af8fe6818a179854a25cb1e00008089d43' 
  AND token = 'AlOiYClck90dj2yZ6F+Ff9VKnHNBMXQwA+cFgSgzkbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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