SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '42d960ebc3f17429a91f9940230d737f6af6482a5e3f7932ab98839cc79f67c2' 
  AND token = 'WGDBUlNKgJ4pctcQPvHBvTLsZfwH0XU4Aaofg3fjtGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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