SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fca787c4e918a5bcfc465a3391fa7746dc4663a8fbc14be6b924b70bb2d5df8' 
  AND token = '2DBxlB6hSPN1vwPnLwERf0QoXPkMF48bLaYqQhQeCFk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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