SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b63f1634fdca5ac07281a21ffadf6f91c88550c0ddab0b635b4f75be318cca5d' 
  AND token = 'oWnDz5ng0sqL2sXsKjuaNoz+UPG5dMrZzMCSX2CJvSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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