SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b6915cccfe6430074630bec168124ce51ea7ba6e52b8c2046652299a8480f13' 
  AND token = 'Zoh/lzu6rNNlXHkdauTgCDyV4dC3aoHFWynuXO10AfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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