SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8cdbef2cf39194f615a98fe1418a892984772350668989dd1ba8122c4602a1e7' 
  AND token = 'T680rj2ItvGgnIjK5qk0kyLmWp9niDobRnc0qYdBq1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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