SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ffd2ab9c1c32f0ce1f471c7fafea5918d212daa2e05ba33424dfd6635349318' 
  AND token = 'JCYXz2RpI/qmuLUOtynBJ4dhJOq60N1+U8agWdB7LZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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