SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4e509c95ea99da55d59cabf4db4f983df3a5f46030893175593f708c8a6952c' 
  AND token = 'Y/pt1DGLOJEDHjvQQZWjYEysLHosn9DJbAHmyeWC+zA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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