SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b36edbd6da2f669de58c025ed5e4e48d01448de3bcc735f91e37a115458e3df2' 
  AND token = 'xdDAm2FeXQoyoOPEXMFls2YkK1gEAzstttv8iyZRBqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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