SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e2401c44d0bf6cf4435601476009bfeff58365dac971e289e93857db9da0d50' 
  AND token = '00gdN+K9uIiNHbib1ctLDU8eKaI3l00ZM2VnzqTLKpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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