SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bac828f974b3d1fad6a2239ae4f49f89f63f7c21bd046cff8d494f7a5e33427' 
  AND token = 'b9ECIo4PUdvJ/uvjznmRY+SDPnvx8Ljebuz/BjL0Omc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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