SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f33830acf144078c56032340fb5c526f699af48025114829b34dd0865435e88' 
  AND token = 'aydGpNcK7mxYVj9OpYB5rp2YSCTvLRpz1h8wDWnwnfk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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