SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '812f4a9b6dfa19a69220f7d03f9e4088f81a940575499ac412ea2c622a22a044' 
  AND token = 'ADlx97hWqaIywbnV+HgPqxLY58eWZQ5x23zDGbnDMpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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