SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bffbc1971d50d7d3eac121322251f147d064602805256787ffaa76000d888017' 
  AND token = 'MjAgnRcLvqrTWevo/kb2PaASf+u3qau7D/jTzh9pXFQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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