SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44cc3bfd689618b86eb8666b027e313156af2257a161908e4082ae94f83e0a5a' 
  AND token = 'J7JGaH1Nw9VPu6eZoNzWIVDAtScl+KwGZojnJ6avRAk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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