SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82f152eda587da85a19164b39950f332750be80dff9ae31f457762662965b80c' 
  AND token = 'DCfYtJhkkmnznYO1pZV/Ex2eQv17KLLsxCpomeBdKvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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