SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3451227902abc15be2e89454621f1ef841013f198435d8ccb09dfb8bd902cd0' 
  AND token = '9RfGJXisV6aNuM/vWo22O+uoh39zWY1/LbNiCl+2h7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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