SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '908208a27317ec33587918f3cdd4078a02a698adc33bd56a74c3661fa6e80e9f' 
  AND token = 'gtzAoacfXTebJbJwV2/liPLsKGWMR+sAmcS7WGfhLvw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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