SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '39fdc751da8e51278b9cf97919d6c813c81e060204089e83191d9d3f4f5b870c' 
  AND token = 'q9f/C9MopsIhGGZj5bWtuLCA9tm8Z8H93YXDsf4z7Mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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