SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5c7a127ab705affefdf9bd6871cafced2519380ea8ce0e298945f029698d639' 
  AND token = 'UL155PsviqMlfYAN0bIH4E0/ewtxoo+ThlYB9VTBn94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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