SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b56f6e134a73c02e050245e687dd709c5d8890a5bd83c433aa22458313eca13' 
  AND token = '3tU/NosK3TiTQRlU7oGwjxxUAKUevxvWbfKBuePHbwU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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