SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '700b71185508623928b674158dd57c36542324734e8824c15558a5dd57c28d84' 
  AND token = 'lg0wJN4OY4busw1lA+TYA0mlXe+mUFyAnUL9OOsF3bk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}