SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd278f43cb4c9f02b2860c6ba8dba2d8ae51ca355b1b27d76204b26f7da0859e' 
  AND token = '5zj3GNvO1KydQO9LEl1BY1/AbYKqhLyEx3/0Dzku/gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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