SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '810f20908e2b975ae75384c1a041a666dd7fef2b6a6b11b1f9fa66d3121e42b0' 
  AND token = 'JvCkM7FpGHJsaMydvdITFRAYjfbe4msD/nnyHmTeJOc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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