SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53fb7de3d4543681f0c5f6c75fe11869217e1f79ea3809aba6d338372a347723' 
  AND token = 'dJhhOnnPLbk/bUCKOfmt3CK7w5gEfzaf/QZDvB7FPd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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