SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84044909e71fdf22ecf53a2f9b233f7920af7388ad0b466ee98b883de824640d' 
  AND token = 'DKGjbsJL8wQkJj531QLc/9qfIXcmM7X+pvVwzRF3UOU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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