SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '789a733115ee6e3a7594f1bc67ecd6ce2d342c7b9232a59d524ae86beb822d58' 
  AND token = 'fCs/UDxo5Lz+Jh3Jgpu/zGrI7MpopB1qfmcOaP8ei+c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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