SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6931c92dfcef7c6510ebcdf7175ab9b9035bfef00b52f28298f360661702c996' 
  AND token = 'uItTwue9Elxy535Vo5+vfuDP4ah3WuPGQV3IvcirRDM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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