SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2329e970e165944784636e5d29acea71ea768ab86c14283875fc5c5622d38243' 
  AND token = 'r4QQNb190AqtK9UPLn01b5JZweGOa/G0Wy/zzBS6tcM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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