SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff148685757ed6d3197eb09b8b5a09a2d27caeba570f1e01193dfc20624ac12b' 
  AND token = '3G4C6fNyHTfW4SSDeZ9Owuvqvbowe7YdxyTBJzIqgCE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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