SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec282a35542607dfe84f670300dd2b2285ce4dd4a042c6a4ab96a958c3e920c0' 
  AND token = 'pUylo4WhFWCNu92ayoutoHZ1zHgdIJLaiSTrqd7u+DU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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