SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4598b2e04ac74bc621fc1d9b91ef1d776bd919131dda0a97a91c0f23ce255fc' 
  AND token = 'pJFH1MQDh8jBxnX+HNtx/5Esn1HPZx9wtvHQ2xhxbj0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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