SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '83257065406700b6f326cd42be3691db003e8548f49b3c6fecf62c4aa75a61c4' 
  AND token = 'H/LU4jUvmYB+zbOIl//w21EsoQ85esmPb4kwSf/JC7U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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