SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55addf311ecbad900fd02a84a5d481c5f8739eb69ed23ee912c41bd787ef9abb' 
  AND token = 'TH8FBCsh+rg+L0ZyrEiPGgMDeQY19skfZWVrf08RgrM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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