SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b50b7feefae031c11904fbedcfd83aac9bd3a679337a45e243fd2ee56cdc73d8' 
  AND token = 'IQuxBjo0pf471CH8+eBGOmsOKNmVR8IjMKcUYSHB2kU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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