SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '436717039075cac2ce0073de6d71cd80392c0269254ebd2f279d0aff508e90da' 
  AND token = 'VPxydvbdeYms+7ZtckWPj7thwuNezDgCESu+b2U1tQE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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