SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0b4ea107ab4d6175a95db339c5c76dfcb85b60bbf37a6433783477aa919b41fe' 
  AND token = 'uLdnrYAFmvJfPVVuFVZSesNt/qn2oFMeA3mjfTQjOsk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}