SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f98e11ab63a3eef01bca5ce0166ff5fb85e42cab06f98c6d92771056dd917b3d' 
  AND token = 'Tf0arnLatlOxPFCSgXyuE+r5LpYqP0SysiJkxiRbgLw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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