SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '166d0593dc18b47ddff0f70174ba13ac2f110f9e1f547c5009e1f1a9fa996444' 
  AND token = 'M6lkMR+lDnJfifiVFbP/zeoKOJC5ls+MP9QeJmtVvC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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