SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7ffeb921242da158518f8f077ffbcdc72f170709e76135d86f04adf9a4477f0' 
  AND token = 'AI3Y0aIPeRQiMKythCIFhh8ST9vjCxDngTuV8y4ysrQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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