SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3edc3d05de8ecd5d54511010ea31936888c67fb502e0b60988335601771f5e7' 
  AND token = 'NLbBfkkjyeWrU/vd5bBc2zmNKhMehQ/0XQi188DPKro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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