SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '026212ba05ba38ccc972431e3586f1170f036e984a3e33e15907f977b25db842' 
  AND token = 'uvCgWD6XkO98GcG8OhNzDdFjQyOknHtKArhEbUggBsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00011

JSON explain

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