SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0342ddbc915c321731f6580efec5c100561d9b5d6f25ef4c27643d54895a231' 
  AND token = 'y4AVc19AxL3t/q6ypDQOjRwAlDgJadotjRnkC9kDiOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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