SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd8f1770a6f03eab1d0e20e3076eb635329e7f543a85423858231ba6a524963f8' 
  AND token = 'QR3HzJyvNMSiwCIm1C0Jq1yYXfR7bU26MRyEHaBIg/U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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