SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b7e6cdbdfc8c9efcae3fff33ccda3093e1410a71f20d2609aece34ed7cd3034' 
  AND token = 'X6tE/NKrbbEObYhhVl1GrNKvlHBa4ALfKv2mA24rMmE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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