SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3805a510f2f468a5a45cfae0fd8b42159537079eccb16dbca768807f056f969' 
  AND token = 'IDu4PduyCVSlvZJQKk7zLzXjVjG4Fa3+790NwpV9zh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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