SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635636abb3e3fdc86be8835e2d53e5adecca4c33e02751a46ddfcd7c87223787' 
  AND token = 'QPrEWwWhyNuQ0s8DW3/Xup6YaYuq7cQx2JldiheeJJc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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