SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4a1ae2312fd2bb74d1a4d4701054c920b25cfa8654392f4bb11a692539ed63bb' 
  AND token = 'nVLw88HunPOsq3TatLsN8V0BT31zV7HP8wm/ACiOlU8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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