SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f001f8c9436c5a451719b0edf60bb52a12fb412c745aea52a143be4c85758dd8' 
  AND token = '7io7yIMwTay1IYq4HiLNaV9Wge/W390qLxCrkGJQrno=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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