SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf7af06004a0e391694d31cc8949aa51c5512084969b09bfb26473701e8fa71' 
  AND token = 'GLNExT8ld8nKQDVNvwPhGFfOHBOB1RTHwjWtdLbkdNs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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