SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0e5dce0d599dc8c23e5c6132c4170df5323724771d85a121687f1ef50703650' 
  AND token = 'p3LXNp6GLimjjTAa4o1IAKlP5m1nAiWnI1ljHpMVfEg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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