SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '4f9e55a77e4bea78a165d3d84e598144a2a86e24d74d787424500e9cbb5e8a57' 
  AND token = '8RFNPyQbwyEVelGF2kMMICI1PTuGMTrYYZnAMD7zdKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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