SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd961e7682be09c46bdc85abdf9af9a1f52d0047412c6d633c3165e789fb4c956' 
  AND token = 'LSTxIJ28RlEwoOVCApY0ACaGOGvwyXcz2BsEaADyj7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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