SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '851ef0eb6f4fd67627428b080b41a601d4ff23ad025da9e5d8ec1e99db444ded' 
  AND token = 'J/YT9yTP0ancblyybdpg3/8qNeG2st2RMyKOpxashQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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