SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac090692c13630b12bc37ec2287b2d88c2875e07849aab690eddee9603f40033' 
  AND token = 'v4PUIdA7tCt8a1LeuLn++XTiLgvGqlkfnVaWOzKcxGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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