SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f889bc77523ff67fe14206cf909aafeb70e6441e7300c198011f5f82d0a5513' 
  AND token = 'eRkH0H1SBWwbjoRBQSJoBhavCfb+hV6XxJh0GjrpATA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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