SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4c90503b4275e54cef6e0016f102b790b53eec9e63c1d70525a7de1e13de276c' 
  AND token = '0tpzYDnhI9gxUhoRUtcyRq+BqaI2r2dmMe4sROEUKoA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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