SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd719378d3e4159ba83522c87a70017ad88545af8ccda83cc76b9e2eecab7d4aa' 
  AND token = '0l3faLI5P3Ic6OWvm5Wfl0iXvRsEoWeY6zbJydQjnGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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