SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a338382ba190913e3b595e890e5ef5c3e141d1653981d4b99e7476e6f95913cf' 
  AND token = 'iEDRJ0pBmXp3xMdHXb0jCw+xHWzRGC20ctdZDXNhQxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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