SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e19b114d112218d15f336644bc0cacc460a7b215019521982680ccad0203e1b' 
  AND token = 'BDXD+eC49Mj3llk8olvMRBUyywmKjrV382mPrz/pVZ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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