SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b9b55b0bc01cff1be0ad947cde7c6c6674498a78a301aef4b445dbd49c28180' 
  AND token = 'eLWCYayeMLCL+LhK8OarZ/8ImcvOa72wp9yRGHRCfyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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