SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3305c354db6d941fde7aabb6745ff1cb20ae34fad48e6802e987549bfa593836' 
  AND token = 'jzesMK7EfNHo8EjBsZYAWfmbqf3ks7LvCtNnGf4PnvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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