SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b812849ff7df3c3dc78a9bc20a935b6c9a3c1b238907a057c92272ca4a75b3ce' 
  AND token = '2u4Qs7XY/hWYYzUYdBatUIYW0wn5TqRjyxgAceunSEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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